GatheringByteChannel | API reference | Android Developers (original) (raw)

interface GatheringByteChannel : WritableByteChannel

A channel that can write bytes from a sequence of buffers.

A gathering write operation writes, in a single invocation, a sequence of bytes from one or more of a given sequence of buffers. Gathering writes are often useful when implementing network protocols or file formats that, for example, group data into segments consisting of one or more fixed-length headers followed by a variable-length body. Similar scattering read operations are defined in the [ScatteringByteChannel](/reference/kotlin/java/nio/channels/ScatteringByteChannel) interface.

Summary

Public methods
abstract Long	write(srcs: Array<ByteBuffer!>!) Writes a sequence of bytes to this channel from the given buffers.
abstract Long	write(srcs: Array<ByteBuffer!>!, offset: Int, length: Int) Writes a sequence of bytes to this channel from a subsequence of the given buffers.

Inherited functions
From class Channel Unit close() Closes this channel. After a channel is closed, any further attempt to invoke I/O operations upon it will cause a ClosedChannelException to be thrown. If this channel is already closed then invoking this method has no effect. This method may be invoked at any time. If some other thread has already invoked it, however, then another invocation will block until the first invocation is complete, after which it will return without effect. Boolean isOpen() Tells whether or not this channel is open.
From class WritableByteChannel Int write(src: ByteBuffer!) Writes a sequence of bytes to this channel from the given buffer. An attempt is made to write up to r bytes to the channel, where r is the number of bytes remaining in the buffer, that is, src.remaining(), at the moment this method is invoked. Suppose that a byte sequence of length n is written, where 0 <= n <= r. This byte sequence will be transferred from the buffer starting at index p, where p is the buffer's position at the moment this method is invoked; the index of the last byte written will be p + n - 1. Upon return the buffer's position will be equal to p + n; its limit will not have changed. Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer. This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Inherited functions

From class Channel Unit close() Closes this channel. After a channel is closed, any further attempt to invoke I/O operations upon it will cause a ClosedChannelException to be thrown. If this channel is already closed then invoking this method has no effect. This method may be invoked at any time. If some other thread has already invoked it, however, then another invocation will block until the first invocation is complete, after which it will return without effect. Boolean isOpen() Tells whether or not this channel is open.

From class WritableByteChannel Int write(src: ByteBuffer!) Writes a sequence of bytes to this channel from the given buffer. An attempt is made to write up to r bytes to the channel, where r is the number of bytes remaining in the buffer, that is, src.remaining(), at the moment this method is invoked. Suppose that a byte sequence of length n is written, where 0 <= n <= r. This byte sequence will be transferred from the buffer starting at index p, where p is the buffer's position at the moment this method is invoked; the index of the last byte written will be p + n - 1. Upon return the buffer's position will be equal to p + n; its limit will not have changed. Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer. This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Public methods

write

abstract fun write(srcs: Array<ByteBuffer!>!): Long

Writes a sequence of bytes to this channel from the given buffers.

An invocation of this method of the form c.write(srcs) behaves in exactly the same manner as the invocation

c.write(srcs, 0, srcs.length);

Parameters
srcs	Array<ByteBuffer!>!: The buffers from which bytes are to be retrieved

Return
Long	The number of bytes written, possibly zero

Exceptions
java.nio.channels.NonWritableChannelException	If this channel was not opened for writing
java.nio.channels.ClosedChannelException	If this channel is closed
java.nio.channels.AsynchronousCloseException	If another thread closes this channel while the write operation is in progress
java.nio.channels.ClosedByInterruptException	If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
java.io.IOException	If some other I/O error occurs

write

abstract fun write(
    srcs: Array<ByteBuffer!>!,
    offset: Int,
    length: Int
): Long

Writes a sequence of bytes to this channel from a subsequence of the given buffers.

An attempt is made to write up to r bytes to this channel, where r is the total number of bytes remaining in the specified subsequence of the given buffer array, that is,

srcs[offset].remaining() + srcs[offset+1].remaining() + ... + srcs[offset+length-1].remaining()

at the moment that this method is invoked.

Suppose that a byte sequence of length n is written, where 0 <= n <= r. Up to the first srcs[offset].remaining() bytes of this sequence are written from buffer srcs[offset], up to the next srcs[offset+1].remaining() bytes are written from buffer srcs[offset+1], and so forth, until the entire byte sequence is written. As many bytes as possible are written from each buffer, hence the final position of each updated buffer, except the last updated buffer, is guaranteed to be equal to that buffer's limit.

Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer.

This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.

Parameters
srcs	Array<ByteBuffer!>!: The buffers from which bytes are to be retrieved
offset	Int: The offset within the buffer array of the first buffer from which bytes are to be retrieved; must be non-negative and no larger than srcs.length
length	Int: The maximum number of buffers to be accessed; must be non-negative and no larger than srcs.length - offset

Return
Long	The number of bytes written, possibly zero

Exceptions
java.lang.IndexOutOfBoundsException	If the preconditions on the offset and length parameters do not hold
java.nio.channels.NonWritableChannelException	If this channel was not opened for writing
java.nio.channels.ClosedChannelException	If this channel is closed
java.nio.channels.AsynchronousCloseException	If another thread closes this channel while the write operation is in progress
java.nio.channels.ClosedByInterruptException	If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
java.io.IOException	If some other I/O error occurs